Door latching actuator assembly



1958 c. s. MERTLER DOOR LATCHING ACTUATOR ASSEMBLY 2 Sheets-Shet 1 Filed Oct. 22, 1965 1N\ 'EN TOR.

(HA/P165 5. Ava/Q74 a? J l I Dec. 17, 1968 c. s. MERTLER 3,416,515

DOOR LATCHING ACTUATOR ASSEMBLY Filed 0013. 22, 1965 2 Sheets-Sheet 2 I w a l --7d F 43 6/ 0 23 INVENTOR.

0442165 5. MEPZZ 6/? BY v 7 M;v

United States Patent 3,416,515 DOOR LATCHIN-G ACTUATOR ASSEMBLY Charles S. Mertler, Mansfield, Ohio, assignor, by mesne assignments, to Essex Wire Corporation, Fort Wayne, Ind., a corporation of Michigan Filed Oct. 22, 1965, Ser. No. 502,088 7 Claims. (Cl. 126-273) The invention relates in general to a door latching actuator assembly and more particularly to such an assembly used with a heatable cavity having a movable door and a latch to latch the door closed to close the cavity. The latch may be designed to latch the door closed upon the temperature exceeding a first temperature range.

In many devices such as ovens, incinerators, and furnaces, there is a heatable cavity with a door or other closure to close the cavity. This door is generally closed during operation of the heatable cavity in order to prevent escape of heat and to prevent a dangerous condition. In ovens such as cooking ovens such as used in household ranges, the oven door often has a latch to latch the door shut and the housewife in using the oven often needs to open the door during the cooking or baking operation in order to check on the progress of the cooking operation. However in many such heatable cavities such as incinerators and furnaces and in household ovens during selfcleaning higher temperature operations, a dangerous condition can exist if the door is opened during operation at these higher temperatures. During operation of the heatable cavity in this higher temperature second range, it could be dangerous to the operator if the cavity door were to be opened.

Accordingly an object of the invention is to provide a means to avoid the above mentioned disadvantages.

Another object of the invention is to provide a door latching actuator assembly to latch the door closed upon operation above a first temperature range.

Another object of the invention is to provide a door latching actuator assembly which is actuated in response to an increase in temperature above a first temperature range to prevent a dangerous condition in opening a heatable cavity door.

Another object of the invention is to provide an oven cavity which has a self-cleaning higher temperature range with a door latch actuating assembly to make sure that the door is locked closed during this self-cleaning higher temperature operation.

Another object of the invention is to provide a safety control for an oven door so that the door may not be opened during high temperature operations which would be a heat hazard to the operator.

The invention may be incorporated in a heatable cavity having a cavity wall, a movable door, a latch to latch the door closed to close the cavity, and means to heat the cavity through a first temperature range to a higher temperature second range, a door latching actuator assembly operative to lock the door closed during operations in said second temperature range but not during operations in said first temperature range, comprising, in combination, a temperature responsive actuator mechanism including, a bimetallic member having first and second positions of operation and mounted on said mechanism with one portion of said bimetallic member acting on said mechanism and with said bimetallic member mounted to be responsive to the temperature within the cavity, an operating memher having first and second portions, means connecting said operating member first portion to another portion of said bimetallic member which is movable with temperature changes, said bimetallic member moving from said first to said second position upon temperature rise above the first temperature range into the higher temperature second range and moving from said second to said first position upon a lowering of temperature below said second temperature range, and means to connect said second portion of said operating member to control actuation of the cavity door latch to prevent opening the door upon said bimetallic member being in said second position and to permit opening the door upon said bimetallic member being in said first position.

Other objects and a fuller understanding of the invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a longitudinal sectional view through part of an oven cavity having a door latching actuator assembly in accordance with the invention;

FIGURE 2 is a top view of the actuator assembly removed from the oven cavity;

FIGURE 3 is a longitudinal section on the line 33 of FIGURE 2;

FIGURE 3a is an enlarged view of part of FIGURE 3;

FIGURE 4 is a sectional view on the line 4-4 of FIGURE 2;

FIGURE 5 is an enlarged sectional view on the line 55 of FIGURE 2;

FIGURE 6 is a longitudinal sectional view through part of an oven cavity incorporating a modified door latching actuator assembly;

FIGURE 7 is a bottom view of the actuator assembly removed from the oven cavity;

FIGURE 8 is a top view of the actuator assembly of FIGURE 7 to a reduced scale; and,

FIGURE 9 is an end view of the actuator assembly of FIGURE 7.

FIGURES 1 through 5 shows a preferred embodiment of the invention but the invention is not to be limited by this showing but only by the claims appended hereto. These figures illustrate one of many forms in which the invention may be constructed. FIGURES l-5 show a door latching actuator assembly 11 for use with a heatable cavity 12 having a door 13. The door 13 may be hinged or otherwise attached for cooperation with the heatable cavity 12 and in this embodiment the cavity 12 is an oven cavity such as may be used in household ranges. The cavity 12 may also be a furnace or incinerator and includes means 14 to heat the cavity, and this heating means 14 is shown as an electrical heater mounted inside the cavity 12. This cavity 12 is formed by a double Wall including an outer wall 16 and an inner wall 17. The door 13 has an outer wall or panel 18 and an inner panel 19 as well as a sub-panel 20 spaced between these two walls 18 and 19. Insulation 21 may be provided between the walls 19 and 20 as well as a gasket 22 to seal the opening around the door when the door is closed. Also insulation 23 is provided between the inner and outer walls 16 and 17 of the oven cavity.

A latch mechanism 25 includes a striker plate 26 attached in any suitable manner to the door 13 such as by a rivet 27 to the sub-panel 20. The latch mechanism 25 also includes a hook shaped latch 28 adapted to cooperate with an aperture 29 in the striker plate 26.

A latch housing 31 has first and second generally parallel walls 32 and 33 carrying a pivot pin 34 on which the hook shaped latch is pivoted. The latch housing or frame 31 has a mounting foot 35 for fastening the latch housing 31 by means of a rivet 36 to a sub-wall 37 of the oven cavity 12.

The door latching actuator assembly 11 includes generally a temperature responsive actuator mechanism 41 and a switch mechanism 42. The temperature responsive actuator mechanism 41 includes generally a cylindrical cup-shaped housing 43 having an end wall 44 and a base wall 45. The actuator assembly 11 is generally adapted to be mounted within a sub-cavity 46 between the outer and inner walls 16 and 17 of the heatable cavity 12. An inner wall cover 47 may be attached by a screw 48 to the inner wall 17 to cover this sub-cavity 46. This inner wall cover 47 has a circular aperture 49 to closely receive the actuator housing or frame 43. This actuator housing 43 extends through this aperture 49 into the main oven cavity 12. The base wall of the actuator housing 43 may be attached to the latch housing 31 by rivets 50 passing through apertures 51 in the actuator housing 43. The base wall 45 is a base or common wall between the actuator and latch housings 43 and 31, respectively.

A thermo-responsive or bimetallic member 53 is illustrated as being a bimetallic snap-acting disc. This bimetallic disc 53 is received in the actuator housing 43 near the end wall 44 and is retained therein by a ring or clips 54 which may be spot welded to the housing 43. The outer rim of the bimetallic disc 53 is a portion of the bimetallic member which is adapted to act against the actuator housing 43. The central portion of the bimetallic disc 53 is another portion of the bimetallic member which is adapted to move in response to temperature changes. An operating member 55 or actuator plunger 55 has one end thereof attached loosely but positively to the central area of the bimetallic disc 53. This may be accomplished by having the end of the actuator plunger 55 pass through an aperture in the bimetallic disc 53 and then having this end spun over to positively connect the plunger 55 and bimetallic disc 53, see FIGURE 3a. The base wall 45 of the housing 43 has a central aperture 56 which is preferably square in shape to receive the square cross section of the actuator plunger 55. This aperture 56 thus guides the movement of the actuator plunger 55 along the length thereof. The outer end of the actuator plunger 55 has a forked end 57 to receive the latch 28, and a pivot pin 58 interconnects latch 28 and plunger 55. The bimetallic disc 53 will snap from one side to the other upon changes in temperature and will move the actuator plunger 55 along the length thereof. The actuator plunger 55 pushes and pulls on the pivoted latch 28 close to the pivot pin 34 and this gives a motion amplifying movement to the hook end of the latch 28.

The switch mechanism 42 includes a first or fixed contact 61 mounted in an insulated manner on the base wall or common wall 45 of the actuator housing 43. A movable contact blade 62 has a first end 63 mounted in an insulated manner on the base wall 45. A movable contact 64 is carried on the outer end of the movable contact blade 62 for cooperation with the fixed contact 61. An abutment 65 is carried on one side of the actuator plunger 55 to act on the movable contact blade 62 upon change of the bimetallic disc between first and second positions with temperature changes. Insulation is provided between the abutment 65 and the movable contact 64 and this may be provided by a insulator sleeve 66 on the abutment 65. The switch mechanism 42 is carried inside the actuator housing 43 so as to provide a self-contained actuator mechanism 41 and switch mechanism 42. The actuator mechanism 41 thus will actuate the pivoted latch 28 in response to temperature changes and at the same time will actuate closed the switch 61-64. Conductors 67 and 68 may be connected to the contacts 61 and 64, respectively, for external connection to this switch mechanism 42. This switch mechanism may be used to actuate an indicator lamp to indicate that the door is locked for a self-cleaning temperature range, or may be used for an interlock or other control function in accordance with the higher temperature operation.

In the structure of FIGURES 1-5 the central aperture 56 is square to loosely receive and guide the actuator plunger 55 which is also square in cross section. This prevents rotation of the actuator plunger to prevent the abutment 65 from rotating to a position wherein it could not actuate the switch mechani m 2- 4 OPERATION The door latching actuator 11 may be used to automatically lock the door 13 closed on the heatable cavity 12. The bimetallic disc 53 may be adapted to be in a first position as shown in FIGURE 3 at normal room temperatures, and at temperatures through a first temperature range. This bimetallic disc may be arranged to snap over to the position shown in full lines in FIGURE 1 upon the temperature rising into a second temperature range. The first and second temperature ranges may be defined as those temperatures lying below and above, respectively, the temperature at which the bimetallic member moves from the first to the second position. If this door latching actuator assembly is used on a furnace or an incinerator for example, then this door latching actuator assembly will automatically lock the door 13 closed to prevent opening the door during operation of the furnace or incinerator in a higher second temperature range which might be dangerous to an operator opening the door 13. If the door latching actuator assembly 11 is used on an oven such as in a household range, then this actuator assembly may be used on such an oven which has a selfcleaning second higher temperature range higher than a first normal cooking temperature range. Such a normal cooking temperature or operative temperature range may be up to about 550 F. for normal food cooking operation. A second higher temperature range may be provided for self-cleaning of the oven. This higher temperature range may be up to about 750 to 900 or 950 degrees F. to burn off any food deposits on the walls of the oven cavity 12. A dangerous condition could exist if a housewife should inadvertently open the door during this higher tempera ture range of self-cleaning operation because an unexpected blast of hot air could be emitted from the open door. Accordingly the door latching actuator assembly 11 may be provided to automatically lock the door 13 closed wherever the temperature inside the oven cavity exceeds the first temperature range. The bimetallic disc 53 may be arranged to snap from the first position shown in FIGURE 3 to the second position shown in FIGURE 1 upon exceeding a temperature of about 550 to 600 degrees. Thus the oven door 13 would be locked closed during the high temperature operation. During subsequent cooling operation the bimetallic disc 53 may snap over to the first position shown in FIGURE 3 at some temperature perhaps 25 or 50' degrees lower than the temperature at which it initially snapped to the second position. This will again unlock the door 13 at a temperature which will not cause an unsafe condition should the door be opened at that temperature.

FIGURES 6, 7, 8, and 9 show a modification of a door latching actuator assembly 71 which again may be used with a heatable cavity 12 and oven door 13. A latch mechanism 72 may include a striker plate 73 fastened on the door 13 and a latch pin 74 cooperable therewith. This latch pin 74 is carried for sliding movement on a latch housing or frame 75. The frame 75 need not be in the form of an enclosing housing. A latch lever 76 is pivoted by a pivot pin 77 to the latch housing 75. The forward end of the latch lever 76 has a forked end 78 to engage a crosspin 79 on the latch pin 74. A rearward extension 80 on the latch lever 76 has a fork 81 to engage an edge of a bimetallic member 82 illustrated as a bimetallic disc. The bimetllic disc 82 has a first portion at one edge which is loosely but positively clamped relative to the latch housing 75 by a rivet 83. Another rivet 84 loosely but firmly attaches the center of the bimetatllic disc 82 to the latch housing 75. The bimetallic disc 82 is cup shaped so as to have first and second concavo-convex positions with the second position as shown in full lines in FIGURE 6 and the first position as shown in dotted lines in this FIGURE 6. The rivet is diametrically opposite the fork 81 so that as the bimetallic disc 82 snaps from the first to the second position the latch lever 76 will be actuated to cause the loach pin 74 to cooperate with the striker plate 73.

The rearward extension 80 of the latch lever 76 extends through an aperture 85 in the latch housing or frame 75 in order to have the fork 81 engage the bimetallic disc 82. When this disc 82 is snapped into the first position, shown in dotted lines in FIGURE 6, the peripheral edge of this disc will engage the latch frame 75 and the central area of this disc 82 will engage the head of the rivet 84, in order to establish a definite temperature at which the bimetallic disc 82 will snap into the second position, shown in full lines in FIGURE 6.

Because the insulation 23 surround the sub-cavity 46 in which the actuator assembly 71 is located, the bimetallic member 82 is responsive to the temperature within the oven cavity 12.

A switch mechanism 87 is provided as a part of the door latching actuator assembly 71. This switch mechanism 87 may include a stack 88 carried on the housing 75. A first contact 89 is carried in the stack 88 on a first blade 90. A second or movable contact 91 is carried on a second blade 92 in the stack 88 for cooperation with the first contact 89. An abutment 93 is carried on one side of the latch lever 76 and is insulated from the contact 91 preferably by an insulator sleeve 94 on the abutment 93.

OPERATION The modification of FIGURES 6-9 may operate in a generally similar manner to the preferred embodiment of FIGURES 1-5. When the temperature in the oven cavity 12 rises above a predetermined temperature, the bimetallic disc 82 will snap over from the first position, shown in dotted lines in FIGURE 6, to the second position shown in full lines in this FIGURE 6. The bimetallic disc 82 is loosely held by the rivets 83 and 84 so that the edge of the bimetallic disc which cooperates with the fork 81 will have a motion amplified movement. This movement will be transmitted to the latch lever 76 and to the latch pin 74 so that it will latch behind the striker plate 73, This will lock the oven door 13 closed so that it cannot inadvertently be opened during operation at the higher temperature range above the temperature of actuation of the bimetallic disc 82. The length of the lever arm between the fork 81 and pivot pin 77 is less than the length of the lever arm between pivot pin 77 and the crosspin 79. This also provides a motion amplifying movement to the latch pin 74.

As the bimetallic disc 82 snaps from the first to the second position the abutment 93 will actuate the contacts to the open condition. By rearranging the switch mechanism 77 this may also be changed to have this switch mechanism moved to the closed condition, in a manner similar to that shown for the embodiment of FIGURES 1-5. Again this switch mechanism 87 may be used to control an indicator lamp or to control an interlock or other control functions. Both embodiments provide an automatic latch to lock a door closed for a heatable cavity wherever the temperature rises beyond a predetermined temperature into a second temperatue range. It will be noted that both embodiments of the invention provide a safety feature to prevent the door 13 from being opened during high temperature operation and this safety feature is automatically provided in accordance with temperature change, rather than merely in accordance with a time function.

In both modifications of FIGURES 1-5 and FIGURES 69 there is an operating member connecting a movable portion of the bimetallic member which controls validation or actuation of the cavity door latch. In FIGURES 1-5 this is eiTected by the actuator plunger 55 directly acting on the pivoted latch 28. In FIGURES 6-9 this is controlled by the latch lever 76 acting on the latch pin 74.

The present disclosure includes that contained in the appended claims, as well as that of the foregoing description. Although this invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts and steps may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

What is claimed is:

1. In a heatable cavity having a cavity wall, a movable door to close the cavity, and means to heat the cavity through a first temperature range to a higher temperature second range,

the provision of a door latching actuator assembly operative to latch the door closed during operations in said second temperature range but not during operations in said first temperature range, comprising, in combination,

a temperature responsive actuator mechanism including, a bimetallic member having first and second positions of operation and mounted on said mechanism with one portion of said bimetallic member acting on said mechanism and with said bimetallic member mounted to be responsive to the temperature within the cavity,

an operating member having first and second portions,

means connecting said operating member first portion to another portion of said bimetallic member which is :movable with temperature changes,

said bimetallic member moving from said first to said second position upon temperature rise above the first temperature range into the higher temperature sec ond range and moving from said second to said first position upon a lowering of temperature below said second temperature range,

a latch mechanism having first and second parts connected to the cavity wall and to the door, respectively, to cooperate together.

means connecting said second portion of said operating member to directly actuate one of said latch parts to prevent opening the door upon said bimetallic member being in said second position and to permit opening the door upon said bimetallic member in said first position,

a switch mechanism,

said operating member being an actuator plunger movable along the length thereof by means of said himetallic member,

means on said actuator mechanism having an aperture to loosely receive and guide said actuator plunger,

and means on said actuator plunger to actuate said switch mechanism as said bimetallic member moves between said first and second positions.

2. In a heatable cavity having a cavity wall, a movable door to close the cavity, and means to heat the cavity through a first temperature range to a higher temperature second range,

the provision of a door latching actuator assembly operative to latch the door closed during operations in said second temperature range but not during operations in said first temperature range, comprising, in combination,

a temperature responsive actuator mechanism including, a bimetallic member having first and second positions of operation and mounted on said mechanism with one portion of said bimetallic member acting on said mechanism and with said bimetallic member mounted to be responsive to the temperature within the cavity,

an operating member having first and second portions,

means connecting said operating member first portion to another portion of said bimetallic member which is movable with temperature changes,

said bimetallic member moving from said first to said second position upon temperature rise above the first temperature range into the higher temperature second range and moving from said second to said first position upon a lowering of temperature below said second temperature range,

a latch mechanism having first and second parts connected to the cavity wall and to the door, respectively, to cooperate together, 4

means connecting said second portion of said operating member to directly actuate one of said latch parts to prevent opening the door upon said bimetallic member being in said second position and to permit opening the door upon said bimetallic member in said first position,

a switch mechanism having a first contact carried relative to said actuator mechanism,

a movable contact blade having one portion thereof carried relative to said actuator mechanism,

a movable contact on said movable contact blade adapted for cooperation with said first contact,

an abutment on said operating member positioned to actuate said movable contact blade to relatively actuate said contacts upon said bimetallic member moving between said first and second positions,

and insulating means between said operating member and said movable contact.

3. A door latching actuator assembly as recited in claim 2, including said insulating means carried on said abutment to close said contacts upon said bimetallic member moving from said first to said second position.

4. In a heatable cavity having a cavity wall, a movable door to close the cavity, and means to heat the cavity through a first temperature range to a higher temperature second range,

the provision of a door latching actuator assembly operative to latch the door closed during operation in said second temperature range but not during operation in said first temperature range, comprising, in combination,

a temperature responsive actuator mechanism and a switch mechanism,

said temperature responsive actuator mechanism including,

a bimetallic member having first and second positions of operation and mounted on said actuator mechanism with one portion of said bimetallic member acting on said actuator mechanism and adapted to be responsive to the temperature within the cavity,

an operating member having first and second portions,

means connecting said operating member first portion to another portion of said bimetallic member which is movable with temperature changes,

said bimetallic member moving from said first to said second position upon temperature rise above the first temperature range into the higher temperature second range and moving from said second to said first position upon a lowering of temperature below said second range,

a latch mechanism having a latch plunger and a striker plate connected to the cavity wall and to the door, respectively, to cooperate together,

and means to connect said second portion of said operating member to move said door latch plunger into cooperation with said striker plate to prevent opening the door upon said bimetallic member being in said second position and to permit opening the door upon said bimetallic member being in said first position;

said switch mechanism including a first contact carried relative to said actuator mechanism,

a movable contact blade having one end thereof carried relative to said actuator mechanism,

a movable contact on said movable contact blade adapted for cooperation with said first contact,

and an abutment carried on said operating member to be moved therewith and positioned to engage said movable contact blade to open the contacts upon said himetallic member moving from said first to said second position.

5. In an oven having an insulated oven cavity, a movable door, a latch to latch the door closed, and means to heat the oven to an operative temperature range and to a higher temperature cleaning range,

the provision of a door latching actuator assembly operative to latch the door closed during high temperature cleaning operations but not during operation in said operative temperature range, comprising, in combination,

a temperature responsive actuator mechanism and a switch mechanism;

said temperature responsive actuator mechanism including an actuator frame,

a thermo-responsive member having first and second positions of operation and mounted on said actuator frame with one portion of said thermo-responsive member acting on said actuator frame and adapted to be responsive to the temperature within the oven cavity,

an actuator plunger attached at one end thereof to another portion of said thermo-responsive member which is movable with temperature changes,

a base on said actuator frame with an aperture therein,

said actuator plunger extending through said aperture in said base,

'said thermo-responsive member moving from said first to said second position upon temperature rise above the operative temperature range into the higher temperature cleaning range and moving from said second to said first position upon a lowering of temperature into said operative temperature range,

means to connect the opposite end of said actuator plunger to control actuation of the oven door latch to prevent opening the oven door upon said thermoresp'onsive member being in said second position and to permit opening the oven door upon said thermoresponsive member being in said first position;

said switch mechanism including a fixed contact fixed relative to said actuator frame,

a movable contact blade having one end thereof fixed relative to said actuator frame,

a movable contact on said movable contact blade adapted for cooperation with said fixed contact, and an insulator abutment carried on said actuator plunger to be moved therewith and positioned to engage said movable contact blade to actuate the contacts upon said thermo-respon'sive member moving between said first and second positions.

6. In an oven having an inner wall defining an oven cavity closable by a movable door provided with a latch having latched and unlatched conditions and means to heat the oven to an operative temperature range and to a higher cleaning temperature range,

the provision of a door latching actuator assembly operative to latch the door closed during high temperature cleaning operations but not during operation in said operative temperature range, comprising, in combination,

a temperature responsive actuator mechanism and a switch mechanism;

said temperature responsive actuator mechanism including an actuator housing adapted to be mounted fixedly to the inner wall of the oven cavity and adapted to extend through and be closely received in an aperture in the inner wall of the oven to be disposed primarily in the oven cavity,

a snap-acting bimetallic disc having first and second positions of operation and mounted in said actuator housing with the periphery of the disc engaging the wall of the actuator housing,

an actuator plunger fixedly attached at one end thereof to the central portion of said bimetallic disc,

a base wall on said actuator housing with an aperture therein centrally of said actuator housing,

said actuator plunger extending through said central aperture in said base wall,

said bimetallic disc snapping over from said first tosaid second position upon temperature rise above the operative temperature range into the higher temperature cleaning range and snapping from said second to said first position upon a lowering of temperature into said operative temperature range,

means to connect the opposite end of said actuator plunger to control actuation of the oven door latch to prevent opening the oven door upon said bimetallic disc being in said second position and to permit opening the oven door upon said bimetallic disc being in said first position;

said switch mechanism including a fixed contact fixed to said base wall,

a movable contact blade having one end thereof fixed to said base wall and positioned inside said actuator housing,

a movable contact on said movable contact blade adapted for cooperation with said fixed contact,

and an insulator abutment carried inside said actuator housing on said actuator plunger to be moved therewith and positioned to engage said movable contact blade to close the contacts upon said bimetallic disc being moved into said second position.

7. In an oven having an oven wall defining a cavity with a hinged door and means to heat the oven to an operative temperature range for normal baking operation and means to superheat the oven for a self-cleaning operation,

the provision of a door latching assembly operative to latch the door closed during superheat cleaning operation but not during normal baking operation, comprising, in combination,

a latch mechanism, a switch mechanism, and a temperature responsive actuator mechanism;

said latch mechanism including an apertured striker plate adapted to be mounted fixedly to the oven door near the outboard end thereof remote from a hinge means thereof,

a latch,

a latch housing fixed to the oven wall,

means to pivotally mount said latch on said latch housing for selective engagement in the aperture in said striker plate;

said temperature responsive actuator mechanism including an actuator housing mounted on said latch housing and adapted to extend through and be closely received in an aperture in the wall of the oven to be disposed primarily in the oven cavity,

a snap-acting bimetallic disc having first and second positions of operation and mounted in said actuator housing with the periphery of the disc engaging the wall of the actuator housing,

an actuator plunger fixedly attached at one end thereof to the central portion of said bimetallic disc,

a common Wall between said actuator and latch housings with an aperture therein centrally of said actuator housing,

said actuator plunger extending through said central aperture in said common wall,

said bimetallic disc snapping over from said first to said second position upon temperature rise above the temperature of said normal baking operation into the range of said superheat cleaning operation and snapping from said second to said first position upon a lowering of temperature into said normal baking temperature range,

means to cause the opposite end of said actuator plunger to act on said pivoted latch near the pivot thereof for a motion amplifying movement of said latch upon snap acting movement of said bimetallic disc between said first and second positions;

said switch mechanism including a fixed contact fixed to said common wall,

a movable contact blade having one end thereof fixed to said common wall and positioned inside said actuator housing,

a movable contact on said movable contact blade adapted for cooperation with said fixed contact, and an insulator abutment carried inside said actuator housing on said actuator plunger to be moved therewith and positioned to engage said movable contact blade to close the contacts upon said latch being moved into the latched position relative to said striker plate.

References Cited UNITED STATES PATENTS 1,413,990 4/1922 McClure l26-197 3,362,398 1/1968 Fane 12619 7 X 3,050,048 8/1962 Scott 126-273 CHARLES J. MYHRE, Primary Examiner.

EDWARD G. FAVORS, Assistant Examiner.

U.S. Cl. X.R. 

1. IN A HEATABLE CAVITY HAVING A CAVITY WALL, MOVABLE DOOR TO CLOSE THE CAVITY, AND MEANS TO HEAT THE CAVITY THROUGH A FIRST TEMPERATURE RANGE TO A HIGHER TEMPERATURE SECOND RANGE, THE PROVISION OF A DOOR LATCHING ACTUATOR ASSEMBLY OPERATIVE TO LATCH THE DOOR CLOSED DURING OPERATIONS IN SAID SECOND TEMPERATURE RANGE BUT NOT DURING OPERATIONS IN SAID FIRST TEMPERATURE RANGE, COMPRISING, IN COMBINATION, A TEMPERATURE RESPONSIVE ACTUATOR MECHANISM INCLUDING, A BIMETALLIC MEMBER HAVING FIRST AND SECOND POSITIONS OF OPERATION AND MOUNTED ON SAID MECHANISM WITH ONE PORTION OF SAID BIMETALLIC MEMBER ACTING ON SAID MECHANISM AND WITH SAID BIMETALLIC MEMBER MOUNTED TO BE RESPONSIVE TO THE TEMPERATURE WITHIN THE CAVITY, AN OPERATING MEMBER HAVING FIRST AND SECOND PORTIONS, MEANS CONNECTING SAID OPERATING MEMBER FIRST PORTION TO ANOTHER PORTION OF SAID BIMETALLIC MEMBER WHICH IS MOVABLE WITH TEMPERATURE CHANGES, SAID BIMETALLIC MEMBER MOVING FROM SAID FIRST TO SAID SECOND POSITION UPON TEMPERATURE RISE ABOVE THE FIRST TEMPERATURE RANGE INTO THE HIGHER TEMPERATURE SECOND RANGE AND MOVING FROM SAID SECOND TO SAID FIRST POSITION UPON A LOWERING OF TEMPERATURE BELOW SAID SECOND TEMPERATURE RANGE, A LATCH MECHANISM HAVING FIRST AND SECOND PARTS CONNECTED TO THE CAVITY WALL AND TO THE DOOR, RESPECTIVELY, TO COOPERATE TOGETHER. MEANS CONNECTING SAID SECOND PORTION OF SAID OPERATING MEMBER TO DIRECTLY ACTUATE ONE OF SAID LATCH PARTS TO PREVENT OPENING THE DOOR UPON SAID BIMETALLIC MEMBER BEING IN SAID SECOND POSITION AND TO PERMIT OPENING THE DOOR UPON SAID BIMETALLIC MEMBER IN SAID FIRST POSITION, A SWITCH MECHANISM, SAID OPERATING MEMBER BEING AN ACTUATOR PLUNGER MOVABLE ALONG THE LENGTH THEREOF BY MEANS OF SAID BIMETALLIC MEMBER, MEANS ON SAID ACTUATOR MECHANISM HAVING AN APERTURE TO LOOSELY RECEIVE AND GUIDE SAID ACTUATOR PLUNGER, AND MEANS ON SAID ACTUATOR PLUNGER TO ACTUATE SAID SWITCH MECHANISM AS SAID BIMETALLIC MEMBER MOVES BETWEEN SAID FIRST AND SECOND POSITIONS. 